Human rights groups have renewed calls for the Thai government to solve the case of the disappearance and suspected murder of a leading Muslim human rights lawyer five years ago. The lawyer's widow has placed her hope in the government of Prime Minister Abhisit Vejjajiva to stand by recent promises to determine who was involved in the case.

Somchai, who chaired the Muslim Law Professionals' Association, has not been seen since.

He had represented clients in several high-profile human rights cases, including several men allegedly involved with links to the regional terror network, Jemaah Islamiyah.

Investigations into his disappearance led to the arrest of five policemen, accused of abducting Somchai from his car in Bangkok on March 12, 2004. One police officer was found guilty on a minor charge. The case is being appealed.

Mr. Somchai's widow, Angkhana Neelapaichit, has consistently pressed Thai authorities to complete the investigation. She accuses officials of interference in the case.

"In the last five years, the case of Somchai Neelapaichit has been interfered [with] by many of the politicians and high-ranking officials, especially the police. But what I am really concerned is the high [level] police official involved with Somchai abduction are still working and they still have power," she said.

Democratic Party member Kraisak Choonhavan says questions still remain about who ordered Somchai Neelapaichit's abduction.

"The curious case of Mr. Somchai's disappearance is that most of us know that he was kidnapped by five policemen involved and then murdered. What we cannot prove, given enough evidence, enough to convict these five policemen. We know that the five took Mr. Somchai, who was involved, directly involved - but how the action took place must have an order from above," said Kraisak.

Retired Australian judge Elizabeth Evatt, a member of the International Commission for Jurists, which has closely monitored the case, says the 2006 court decision and the consequent delays were a violation of justice. Appeals to the verdict are pending.

"Three years down the track, the appeal is still pending and the cross appeal too. So I find that really quite appalling. It is a case of justice delayed, justice denied; a violation of a most important principle," she said.

Angkhana Neelapaichit's hopes of a resolution were raised when the government of Prime Minister Abhisit Vejjajiva came to power in December. At a January dinner for foreign correspondents, Mr. Abhisit said there was a "good chance" of progress in the investigation.

The U.S.-based group Human Rights Watch called on the government Thursday to ensure those responsible for Mr. Somchai's disappearance and what it calls his "presumed murder" are brought to justice.

Meanwhile, Thai Deputy Prime Minister Suthep Thaugsuban is reported as saying there may be fresh prosecutions as there is now sufficient evidence to lay charges against those involved with the Somchai abduction.